Cable operated controls are utilized in a number of control systems. For example a clutch mechanism in a manual shift automobile is often connected by means of a flexible control cable to a clutch pedal mounted on the fire wall separating the engine compartment from the passenger compartment. In addition flexible control cables are often utilized in brake systems where a brake is connected by means of a flexible control cable to a brake pedal also mounted on a fire wall.
The control cables in such systems often require adjustment in order to accommodate manufacturing tolerances in the cable itself or in the controlled member operated by the cable. Further adjustment may be required after a period of use to accommodate wear in the cable and attachments including sheaves or in the member controlled by the cable.
For example in a manual shift system, the clutch mechanism facing plate wears during use resulting in the relatively heavy clutch spring drawing the control cable further towards the clutch mechanism and effectively shortening the cable whereby play will be introduced between the clutch pedal and the control cable. In brake systems, the opposite result occurs, that is, the effective length of the cable is lengthened as brake shoes wear down again resulting in undesirable play being introduced into the brake system.
Such cable control systems can be adjusted manually to achieve the desired regulation but this usually requires shutting down of the system (in the case of an automobile, taking it to a garage) and obtaining the services of a mechanic.
Various structures have been proposed in the past to provide for a self-adjusting feature to assure proper tensioning of a control cable in a control system. Such devices have, however, been expensive to manufacture and often took up an undue amount of space. In many vehicles, particularly compact vehicles, space in the engine compartment is limited and it is often difficult to provide space between the fire wall and a member to be controlled in which to position any self-adjusting control device.
It is therefore an object of our invention to provide for a self-adjusting control device which is inexpensive to manufacture and which will be able to accommodate either effective shortening or lengthening of the control cable due to wear of parts making up the control cable system or as may be required to accommodate manufacturing tolerances.
It is a further object of our invention to provide for a self-adjusting control cable device which will occupy a minimum amount of space and which may be anchored to a fire wall separating the engine and passenger compartments or may be included anywhere in the control system between the member to be controlled and an actuation member for effectuating control.